Format

Send to

Choose Destination
J Lipid Res. 2015 Jan;56(1):109-21. doi: 10.1194/jlr.M055004. Epub 2014 Nov 24.

CGI-58/ABHD5 is phosphorylated on Ser239 by protein kinase A: control of subcellular localization.

Author information

1
Research Unit Functional Proteomics and Metabolic Pathways, Institute of Pathology, Medical University of Graz, Graz, Austria A-8036, and Omics Center Graz, BioTechMed-Graz, Graz, Austria A-8010.
2
Rutgers Center for Lipid Research, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 Departments of Nutritional Sciences Rutgers, The State University of New Jersey, New Brunswick, NJ 08901.
3
Rutgers Center for Lipid Research, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 Food Science, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901.
4
Institute of Molecular Biosciences, University of Graz, Graz, Austria A-8010.

Abstract

CGI-58/ABHD5 coactivates adipose triglyceride lipase (ATGL). In adipocytes, CGI-58 binds to perilipin 1A on lipid droplets under basal conditions, preventing interaction with ATGL. Upon activation of protein kinase A (PKA), perilipin 1A is phosphorylated and CGI-58 rapidly disperses into the cytoplasm, enabling lipase coactivation. Because the amino acid sequence of murine CGI-58 has a predicted PKA consensus sequence of RKYS(239)S(240), we hypothesized that phosphorylation of CGI-58 is involved in this process. We show that Ser239 of murine CGI-58 is a substrate for PKA using phosphoamino acid analysis, MS, and immuno-blotting approaches to study phosphorylation of recombinant CGI-58 and endogenous CGI-58 of adipose tissue. Phosphorylation of CGI-58 neither increased nor impaired coactivation of ATGL in vitro. Moreover, Ser239 was not required for CGI-58 function to increase triacylglycerol turnover in human neutral lipid storage disorder fibroblasts that lack endogenous CGI-58. Both CGI-58 and S239A/S240A-mutated CGI-58 localized to perilipin 1A-coated lipid droplets in cells. When PKA was activated, WT CGI-58 dispersed into the cytoplasm, whereas substantial S239A/S240A-mutated CGI-58 remained on lipid droplets. Perilipin phosphorylation also contributed to CGI-58 dispersion. PKA-mediated phosphorylation of CGI-58 is required for dispersion of CGI-58 from perilipin 1A-coated lipid droplets, thereby increasing CGI-58 availability for ATGL coactivation.

KEYWORDS:

Chanarin Dorfman syndrome; adipocytes; adipose tissue; adipose triglyceride lipase; lipase; lipid droplets; lipolysis; perilipin

PMID:
25421061
PMCID:
PMC4274058
DOI:
10.1194/jlr.M055004
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center